Solar Electric UTV (Polaris sucks, Bad Boy Buggy sucks, Club Car wins)

Step 1 completed:  Acquired a used late-80s EZGO 36V golf cart with charger locally for a decent price.  It uses 6 X 6V batteries wired in series.  As per the weblink in the 8/12/2022 entry above, I'm hoping over time to mount a 300W solar panel on the roof and run the power through an appropriate controller into the battery pack.  Now having driven the cart a bit on our terrain, I feel no compulsion to up the power on the unit as the person in the web-link had done.....with our flat property and no 'need for speed', the torque provided by the electric motor is more than sufficient for bucket hauling and moving light loads of wood.

One question I have relates to battery maintenance....as this acquisition is encouraging me to learn more about deep cycle battery feeding and care.  The current batteries in the cart are standard lead-acid deep cycle golf cart batteries.  Although it would be an expensive exchange, I could get into "36V golf cart replacement packs" of lithium batteries, in this case three batteries, each battery (36V/60 Ah) wired in parallel.  Truthfully, my own reason for wanting to do this is to lighten the load, lighten transfer of the batteries for storage in the off-season, and potentially have a more worry-free battery over their life-span.....(??)....yes?....maybe?  Are there additionally any benefits or drawbacks to a lithium vs lead acid battery system when designing a solar charging system around them?  I've read that 6 X 6V systems will out perform 3 X 12V configurations (series wiring) in power and averaged duration before re-charging but don't know how this may relate to the 36V parallel wired batteries now being offered and that I'm considering.

At this point I'm impressed with what the unit can do and how little charge we have used up in short trips around the homestead. Thoughts on the above?  Thanks!.....

Edit:  Looks like the replacement pack in question is actually 3 X 12V series-wired Lithium iron phosphate batteries.  They sell 36V batteries, but the golf cart replacement pack is not sold that way.

I may have a contender for this use.  Taylor Dunn has made electric utility carts for decades, mainly for industrial uses.  I just picked up a B2-48 that was made in 2005.  It already has a solid-state controller.  One downside is there isn't a lot of room between the seat and the steering wheel and foot pedals.  If you are a large-frame person you might have problems.  However, they are considered bulletproof.  The one I got is rated to carry something like 3,000 lbs and tow 12,500 lbs.  That is probably on a level paved surface, but still that is more than I will ever need for work around my homestead.   There are configurations available with a 2nd row of seats and I think they will fold down to a larger flatbed.

It seems like the concept of electric vehicles (EVs) is spilling over into the rural/farm sector at an increasing rate.  Many if not most of the major agricultural equipment brands are offering some sort of electric version of an ATV/UTV at this point and no doubt they have been able to borrow extensively from the decades of technology development in the golf cart sector.  While I'm still interested in solar juicing my current golf cart with a rooftop panel, I'm being seduced by current ads for some of the newer golf cart/UTV offerings, some from traditional manufacturers and some from new start-ups.  Typically these are 48V or higher, but there's a new twist if I'm reading the history correctly:  AC motors instead of DC motors as the power plant of the vehicle.  Although there may be advantages of an AC motor over a DC motor, it appears there's added complications as the DC current from the batteries needs to be converted to AC.  Minimally this would seem to incur a power cost.  Additionally, when I inquired at a local sales outlet about replacing the lead acid batteries with LiFePO4 (48V driving AC motor) they responded that some interface changes would need to be done and would not be something they could do locally.

Have any other tweakers and DIY-ers out there encountered these issues in the farm-based electric vehicle realm?  Is the AC motor the new trend and is it likely to phase out the DC motors of past electric golf carts?  I'm certainly finding that, as an 'ageing homesteader', these vehicles are worthy companions in getting work done.  Thanks!....

So I hope it's not considered a hijack of this thread to continue to post on progress in outfitting an older 36V golf cart (EZ-GO) to supplemental solar charging.  I've decided to stick with lead acid batteries (6 batteries @ 6V/225 Ah) until next year, but went ahead with a local purchase of a used solar panel:  original rating of 327W, ~54 V, and ~ 6 A.  See the link in the  8/12/2022 entry above for some background and this link for specs on the panel:  https://us.sunpower.com/sites/default/files/media-library/data-sheets/ds-e20-series-327-residential-solar-panels.pdf

In the video link from the 8/12/2022 entry above, a charge controller is recommended that, upon inspection of the specs, does not have a setting for LiFePO4 batteries.  Yet it appears that some manufacturers of MPPT charge controllers do in fact sell controllers that can adjust between both lead acid and LiFePO4 types of batteries.  Can anyone here please recommend a charge controller that may fit the bill for my system that I could use now for my lead acid batteries, but also use when I've switched to LiFePO4?  Also, if I connect the output (from the controller) to the leads that originate from the charging plug (grid powered stock cart charger -- 36V/18A), will this cause problems when I want to use the stock charger or will the controller sense this and not allow 'backfeed' of current into the solar charge controller and panel?  

Thanks for any questions, comments and recommendations you can offer!....

John Weiland wrote:In the video link from the 8/12/2022 entry above, a charge controller is recommended that, upon inspection of the specs, does not have a setting for LiFePO4 batteries.  Yet it appears that some manufacturers of MPPT charge controllers do in fact sell controllers that can adjust between both lead acid and LiFePO4 types of batteries.  Can anyone here please recommend a charge controller that may fit the bill for my system that I could use now for my lead acid batteries, but also use when I've switched to LiFePO4?  Also, if I connect the output (from the controller) to the leads that originate from the charging plug (grid powered stock cart charger -- 36V/18A), will this cause problems when I want to use the stock charger or will the controller sense this and not allow 'backfeed' of current into the solar charge controller and panel?

I bought an EPEver that seems robust for the price and does both LA and LFP, but is only 12 or 24V. I'm seeing others at Amazon in that price range or less with decent reviews if you are willing to go that route. It would be nice to find a source better than Amazon for stuff like this...

paul wheaton wrote: ............Overall, I think that if I could do it all over again, I would get:  a standard body club car (not the long body we have now) with seats in the back that fold down to carry stuff.  The straight axle stuff (no fancy suspension) means there are no boots or wimpy axles to deal with.  And because it is something that is built by the thousands, it is designed for heavy use.  The polaris and the bad boy buggies seem to be built as an occasional use novelty.  I do think I would get something that is just two years old instead of 20+ years old.  

Just going back to the OP and adding some follow-up to my project outlined more in this past link:

https://permies.com/t/221392/PV-panel-hook

It's now been several weeks since the install and the system has exceeded my expectations.  Just going over the finances that involved some new, some used additions on the the base EZ-GO golf cart:

Used 1990 EZ-GO 36V Marathon golf cart       $1500.00 USD    (note:  stock configuration....could be lifted and larger wheels added for clearance)
2 "new" (used) 6V 225 Ah lead-acid batteries to replace 2 that were bad     $100.00
New flip-down seat to replace rear stock configuration                                ~$400.00
Used 327 W solar panel purchased locally                                                        $100.00
MPPT solar charge controller, 40 A, 12/24/36/48 V                                          $150.00
Associated wire/charge status meter/multimeter                                          ~$100.00

So this project cost under $2500.00 (wall charger came with the cart) and as noted in Paul's original post, exploits the oddity that golf carts are built with amazing durability given what they are used for.  It's no secret that changes are afoot and city codes are allowing more "street legalized" carts like this on urban roadways, which in turn is producing a new import market for the ~$10-20K range electric UTV.  The durability and user-friendliness of those new vehicles remains to be seen, but in the meantime the usual media outlets for used items typically have a rotating selection of used golf carts anywhere from sub-$1000 to $10K.  I could have avoided the $400.00 flip seat if I had just waited a bit longer and found a cart that already had one installed....the flip seats are pretty common and allow for a small 'truck bed' like platform when needed.  The stock sun canopy was removed and I bolted on angled metal rail (from any hardware store or big box version) to the existing supports in order to mount the PV panel.

The original thinking was that I would just reduce the frequency of charging from our power grid by virtue of the solar panel.  It's been a pleasant surprise that, given our usage of the cart for just shuttling feed buckets, firewood, etc. around the property, I've not needed to plug it in at all.....and typically charges by solar power back to 100% between uses (northern Minnesota USA, .... will see as winter approaches how long this remains the case).  So much nicer than firing up the various gas/diesel vehicles for similar tasks.  As the cart was used and I sense could use some brake/lubrication work, I probably will spring for just hauling it to a local EZ-GO maintenance/dealer for the once-over.  But as a great starter project, it's been fun and useful to boot!